The perfect way to write an email subject line, and 9 mistakes to avoid

Flickr/Sebastiaan ter Burg

Writing an important work email is one thing. Getting someone to actually open it is the challenge.

Turns out the key to grabbing your recipient's attention is an excellent subject line.

The problem is, most people don't give it much thought. They quickly type something in before clicking "send," or don't bother writing anything at all.

"We call the subject line, 'the most important, most neglected line' in email," says Will Schwalbe, who coauthored "Send: Why People Email So Badly and How to Do It Better" with David Shipley.

But if you want people to read your emails — and respond — you need to craft the perfect subject line.

"It needs to be descriptive, informative, and inviting," says Barbara Pachter, a business-etiquette expert and author of "The Essentials Of Business Etiquette." "You want to target your reader. Often, people will not open an email unless the subject line indicates it's something worth reading."

Here's what the perfect subject line looks like — and nine mistakes to avoid.

The perfect subject line

Your subject line will look different depending on the nature of the email (is it a request? an announcement?) and the recipient(s). But generally speaking, the perfect email subject line "is short, specific, has the most relevant word or words at the start and not at the end, and refers to the conversation at hand — not one from weeks ago," says Schwalbe.

Here's what the perfect subject line looks like:

It's short

A typical inbox reveals about 60 characters of an email's subject line, while a mobile phone shows just 25 to 30 characters, Amanda Augustine, a career advice expert at TopResume, previously told Business Insider. Get right to the point in about six to eight words.

It tells the recipient what the email is about

If your email is a question, your subject line should say something along the lines of, "Question about your service," or "Question about your latest report," Pachter says.

If you're making a suggestion, title your email "Suggestions for today's meeting."

If you're sharing an update or status report, label it as such.

Tell the recipient exactly what they can expect in the body of the email.

It says something unexpected

Want to stand out? Include surprising information, such as "I'm relocating to our Dublin office!" – but only if it's true.

It drops names

Normally name dropping is obnoxious, but in emails it works.

When you write, "Jacob Jones suggested that I contact you" or "Jen Smith gave me your email address," the recipient may be more likely to open it.

However, do not mention someone's name if you don't know the person, Pachter says.

It provides a call to action

If you need the recipient to take action, or meet a deadline, or be somewhere at a certain time, say so in the subject line!

It communicates good news

Instead of, "Here's what happened at today's meeting," try highlighting the good news: "You were nominated for an award at today's meeting!"

It thanks, congratulates, or compliments the recipient

You can simply use "Thank you" when emailing a thank-you note. You can say "Congratulations" if the recipient was just promoted — or something like "Nice job with today's presentation" if your email talks about why you enjoyed it so much.

Mistake 1: Leaving it blank

Jenna Goudreau, a former deputy editor at Business Insider, writes: "Not including a subject line is one of the biggest mistakes you can make."

She says Augustine stressed that the subject line "can be the most important part of the email, since it often determines whether an email is opened and how the recipient responds. An email with a blank subject line will likely get deleted, lost, or immediately irritate the recipient, who is forced to open the email to figure out what it's about."

Mistake 2: Failing to tell the recipient anything

Avoid using useless subject lines that don't tell the reader anything, like, "???" or "Two Things" or "Question" or "Urgent," says Schwalbe.